Air-control valve for pneumatic conveyers



Feb; 7, 1933. w. A. SMITH 1,896,597

AIR CONTROL VALVE FOR PNEUMATIC CONVEYERS Filed Oct. 27, 1928 Patented Feb. 7, 1933 UNITED STATES PATENT-OFFICE WILLIAM ALLEN SMITH, or MANCHESTER, ENGLAN ASSIGNOR TO PNEUMATIC coN- VEYANGE & EXTRACTION (1929) LIMITED, or LONDON, ENGLAND, A COMPANY or GREAT BRITAIN AIR-CONTROL VALVE FOR PNEUMATIC CONVEYERS I Application filed October 27, 1928, Serial No. 315,536, and in Gre at mam November 5, 1927; r

ries with the nature of the material and inparticular with the size of the individual pieces of the material and the'interstices between them. For instance, in vacuum conveying apparatus and under certain condi-' tions, in which the Weight of the material is a relevant factor, and when the material is of relatively large size, say 7 inch or inch cube, only a very small quantity of auxiliary air is required i. e. air separately ad mitted in addition to that which enters through the interstices of the material.

The object of the present invention is to provide means whereby automatic control of the proportion of the conveying medium may be obtained so as to increase the efiiciency of 2 the plant by reducing power losses by maintaining elficient conditions of conveyance.

According to the invention an automatic control valve is provided operating, with variations of pressures to regulate the admission of auxiliary air.

The invention is particularly applicable to apparatus for flue dust extraction as shown in British Patent No. 281,811 in which the pipes are usually arranged to be across the i width of water tube boilers, with a valve at each end, the one at the far end being an air valve to admit auxiliary air for conveyance for the material. With such apparatus it is necessary for theoperator to open both the 49 valves before the extraction can be effected. As the completion of the extraction is reached, some of the inlet apertures become exposed and an excess of air is admitted to the conveying passage. With the improved automatic valve fitted at the end of the passage, the valve closes progressively with the exposureof the inlets as the degreeiof 'vacuum'falls and so acts to maintain the efliciency of the conveyance.

The accompanying drawing shows a preferred example of the invention, in which:-

Fig. 1 is a sectional side elevation.

Fig. 2 is an end elevation, and

Fig. 3 shows an arrangement for the use of the valve shownin Figs. 1 and-2. As illustrated the valve is arranged in a flanged cover (1 adapted to besecured to the end of the conveying pipe 1?). Centrally of the cover is acircular aperture with three radi'ating webs 0. to support a small central boss (Z for the stem of the valve. On the inner end of the cover and around the circular aperture is a fiat annular seating or packing 6 held in a groove, and of any suitable materia'l. The valve consists of a fiat metal disc 7, secured on the end of aspindle g which is a sliding fit in the central boss d'of the cover, on the outer end of which spindle is arranged a, spring h, washer j, adjusting nut k and locking nut k whereby the initial pressure on the valve maybe adjusted, the spring h acting to hold the valve disc f on to the seatmg 6. V

Obviously the particular constructional details of the valve may be varied without departure from the nature of the invention as already set out above.

As shown in Fig. 3 the valve is particularly applicable to apparatus for flue dust extraction as covered by British Patent No. 281,811. The valve is shown attached by its casing a to one end of a length of piping m which is shaped and formed with inlets n as described in the aforesaid British patent. The pipe is connected through a manually oper-' able control valve 0 with the suction pipe p. The piping m is usually arranged across the width of water tube boilers with a manually operable control valve such as 0 at each end but the use of the automatic air in- 90 let valve gives a better control of and a new result in effecting the pick-up of the material by the balancing of the volume of draft and the suction assisting the entrance of the ma terial at the inlets n.

In operation, on opening the main valve 0, the disc 7 of the automatic valve would be drawn ofl' its seating e to an extent proportional to the existing degree of vacuum in the conveying pipe on and in proportion to the setting of the adjustable spring h.

The use of the valve is not limited to the particular application above described, for instance in some existing installations an auxiliary air supply is used at points other than at the inlet of the material, and the automatic valve may be used in such positions.

From the foregoing it will be obvious that the valve may be used in many instances with considerate advantage. In the example above described there would be an economy effected in the time of the operator, a reduction of the possibility of air leaks into the steam-raising unit and a saving in power in the extracting apparatus.

What I claim is 1. In apparatus for effecting the pick-up of powdered, granular, and like materials,

, for pneumatic conveyance, wherein the material entering a pipe at one point is exposed to a draft of air entering the said pipe from an inlet valve at another point beyond the said entrance for the material, means for efifecting the automatic balancing of the volume of the draft and of the suction assisting the entrance of the material, comprising a self-opening spring-loaded inlet valve as set forth.

2. In apparatus for effecting the pick-up of powdered, granular, and like materials for pneumatic conveyance, according to claim 1, adjustable means for regulating the tension of the loading spring for the valve, as set forth.

' In testimony whereof I have signed my name to this specification.

WILLIAM A. SMITH. 

